Tetraborate detergent compositionx



Patented Dec. 30,- 1952 TETRABORATE DETERGENT AND METHOD OF Phillipsburg, N. J assignor Herbert L. Sanders, to General Aniline This invention relates to an improved detergent composition comprising alkali metal tetraborates in the form of low density beads or pellets having a honeycomb structure, and particularly to such beaded tetraborates containing a substantial amount of a liquid non-ionic watersoluble polyglycol ether surface active agent.

Numerous detergent products are now marketed in the form of light hollow beads or pellets which have been obtained by a spray-drying process where a slurry of an organic deter ent and an inorganic salt (usually sodium sulfate) is atomized into a spray-drying chamber where it falls through a current of hot air and is formed into hollow spheres in the process. Such products have a low bulk density, a low hygroscopicity, rapid solubility and other desirable features. In the productionof such pelleted detergents the organic detergents which have been employed, as well as the inorganic salts or detergents which are mixed therewith, are solids at room temperature. The organic detergents which have been employed in the preparation of beaded detergents include not only the alkali metal soaps of fatty acids, but the alkali metal-usually sodium salts of alkyl aryl sulphonates, petroleum sulfonates, fatty alcohol sulfates and the like.

The'liquld water-soluble non-ionic polyglycol ether surface active agents have not been employed commercially in the production of pelleted detergent compositions by spray-drying processes, although the production of free-flowing powders employing such polyglycol ethersurface active agents by mixing the same with such materials as benzoic or phthalic acid salts, pyrophosphates, meta-phosphates, sodium carbonate, sodium sulfate and other solid powders have been mentioned. It has been found, however, that only a relatively small amount of suchliquid polyglycol ether detergents can be mixed with the various salts which have heretofore been suggested before a paste is formed and separation of liquid occurs. Thus, sodium sulfate will tolerate only about 5 per cent of liquid non-ionic polyglycol ether detergents before a paste is formed. Sodium pyrophosphate will tolerate up to about 18 per cent of the liquid which appears to be the maximum amount which may be mixed with any of the usual inorganic alkali detergents. Calcium chloride in finely powdered form will hold up to 50 per cent of the liquid and remain free flowing, but the resultant mixture has an extremely high hygroscopicity and the calcium chloride has little or no detergent value.

I have now found that alkali metal tetraborates may readily be converted into low density COMPOSITION G THE SAME & Film Corporation, New York, N. Y., a corporation of Delaware 2 Claims. (01. 252-135)- hollow beads either by the conventional spraydrying process or by the novel process more fully disclosed in this application. The thus-obtained low density hollow beads of alkali metal tetraborates are believed to be themselves novel products and have been found to tolerate substantial amounts (about 40 per cent) of liquid nonionic polyglycol ether surface active agents, while still remaining a dry free-flowing product. They thus lend themselves readily to the production of novel dry free-flowing low density hollow beaded detergent compositions consisting of alkali metal tetraborates containing considerable amounts of liquid non-ionic polyglycol ether surface active agents.

It is therefore an object of the present invention to provide novel low density hollow beads of alkali metal tetraborates. A further object of the invention is to provide a novel method of producing such low density hollow beads without recourse to spray-drying, although this technique may be employed if desired. Still a further object is to provide a novel detergent composition in the form of a free-flowing product composed of low density hollow beads of alkali metal tetraborates containing considerable amounts of liquid non-ionic polyglycol ether detergents. Other and further objects will be apparent as the present description progresses.

In practicing the present invention I make use of the fact that alkali metal tetraborates when heated tend to puff up or intumesce by release of water of hydration to give a low density highly porous mass. I have discovered that by heating alkali metal tetraborates in the manner described herein, this porous product can be obtained in the form of low density hollow beads and due to the film-forming characteristics of the tetraborates, these hollow beads can exist without the need of any type of binder, a property not possessed by other alkaline inorganic material such as sodium sulfate, commonly used in beaded detergents.

In my preferred method of producing the low density hollow beads of alkali metal tetraborates, I first convert the alkali metal tetraborate (usually common borax) into small solid granules and then heat these small granules so as to explode the same by'release of water hydration to give the novel low density hollow beads of the present invention. When it is desired to produce a low density hollow beaded detergent composition composed of these low density hollow beads of alkali metal tetraborates containing considerable amounts of liquid non-ionic polyglycol ether surface active agents, I may add the liquid non-ionic polyglycol ether surface active agent to the tetraborate either before the formation of the hollow beads or to the already formed hollow beads. It has been found that if the hollow beads are formed in the presence of the liquid surface active agent, a more careful control over the temperature of the heating must be exercised in order to prevent burning or volatilization of the organic material, and that a somewhat higher temperature is required for the formation of the hollow beads than is otherwise the case,

The details of the present invention may be more readily described in connection with-specific examples thereof, in which the parts are by weight:

Example 1 16 parts of common borax (Na2B4O7.l0H2O) were pasted up with 3 parts of water and placed in a porcelain evaporating dish. Heat was applied from below while the paste was worked to and fro with a spatula. There was first an initial melting phase, after which the paste disintegrated into rather large moist granules and on continued working at higher temperatures these granules dried out and further disintegrated into very small granules of the order of 6.1 mm. On still further working of these granules in contact with the hot surface a swelling or puffing thereof began to set in and in a short time the whole mass was converted to relatively uniform beads of about 1 in size. These beads had a porous honeycomb structure under a microscope. The bulk density of this product was in the neighborhood of 0.1 gram per cubic centimeter. This operation was repeated on a heated metal block containing a thermometer in a cavity and it was determined that the puffing occurs at a temperature slightly above 130 C.

Liquid non-ionic polyglycol ether surface active agents were then added to the thus-obtained hollow beads while simply stirring with a spatula. The surface active agent was readily absorbed into the pellets and a dry free-flowing solid mixture was obtained when up to .0 per cent by weight of the polyglycol ether was added.

The above operation was again carried out using 16 parts of potassium tetraborate (EiiBiOmSHQO) ([NHQ 2240145120) in place of the common borax and this material was found to form low density hollow beads in the manner describe above. The use of a heated block showed that puffing occurred at temperatures above 190 C. obtained low density hollow beads of ammonium tetraborate would absorb up to 46 per cent by Weight of liquid non-ionic polyglycol ether surface active agents to give dry free-flowing solid mixtures.

It was found that the thus- 4 Example 2 Using the procedure described above, 16 parts of borax, 3 parts of water and a parts of a liquid non-ionic polyglycol ether surface active agent were pasted together and worked in a porcelain evaporating dish, heated from below. After an initial melting phase the paste disintegrated into rather large moist granules and on continued heating and working, these granules dried out and further disintegrated into small granules of the order of 0.1 mm. On still further working and heating of these granules in contact with the hot surface, a swelling or puffing of these small granules began to set in and in a short time were converted to relatively uniform beads of about 1 mm. in size. The thus-obtained free-flowing low density hollow beads on analysis were found to contain 57.2 per cent of a partially hydrated sodium tetraborate, 19.4 per cent water (by drying at C.) and 23.4 per cent polyglycol ether surface active agent. The bulk density of this product was 0.15 gram per cubic centimeter.

By carrying out the process on a metal block having a thermometer in a cavity it was found that in the presence of the liquid polyglycol ether surface active agent a higher temperature was necessary to cause pufilng. A temperature range of 200 C. to 300 C. was found most practical. At this high temperature the particles could not be allowed to remain in contact with the heated surface for more than a few seconds at atirne (up to about 10 seconds) without charring of the product resulting.

Example 3 The operation described in the first. paragraph of. Example 1 above was repeated through the formation of the small. dense grains of the borax, the operation being conducted as follows: 16 parts of common borax were pasted with 3 parts of water and placed in a porcelain evaporating dish heated from below and the paste worked with a spatula. After an initial melting phase the paste disintegrated into rather large moist granules and on continued working and heating, these granules dried out and disintegrated into very small grains of the order of 0.1 mm. Further heating and working was then stopped. and the small granules were then passed through a rotary kiln heated to a temperature of C'. at the central part. On passing through the. kiln the materials puffed or exploded in the hot zone to form very uniform. low density hollow beads having. a particle size of about 1 mm, which were continually discharged from the lower end of the kiln. The thus-obtained low density hollow beads of borax were then mixed with liquid non-ionic polyglycol other surface active agents by slowly adding the liquid surface active agent to the beads while stirring them. It was found that up to 40 per. cent of. the liquid polyglycol ether detergents could be incorporated in the beads while still a dry free-flowing beaded product.

Erample 4 In another experiment, 15 parts of borax, 3 parts of water and 4 parts of a liquid non-ionic polyglycol ether surface active agent were pasted together in a porcelain evaporating dish heated from below and worked to and fro with a spatula. As in the previous examples, after an initial melting phase, the paste disintegrated into rather large moist granules which on continued working and heating dried out and further disintegrated into very small granules of the order of belt which passed through an 0.1 mm. Further heating was then stopped and these small granules were then placed on a metal oven held at a temperature range of from 200 C. at the ends to 300 C. in the center. The time of passage through the oven was restricted in a total of seconds. On passing through the oven the small beads puffed or exploded into relatively uniform beads of about 1 mm. in size, so that a dry free-flowing pelleted material containing 30 per cent polyglycol ether surface active agent similar to that obtained in Example 2 above was obtained.

In the foregoing examples a number of liquid non-ionic polyglycol ether surface active agents were tested for their miscibility with the low density hollow beaded alkali metal tetraborates. Among the specific liquid non-ionic polyglycol ether surface active agents which were employed were water-soluble polyglycol ethers obtained by condensing ethylene oxide with alkyl phenols containing 3-12 alkyl carbon atoms. Specific compounds of this type which were employed were the water-soluble condensation products of ethylene oxide with di-tertiary butyl phenol and cresol, iso-octyl phenol and cresol and the mixed alkyl phenols obtained by condensing phenol and cresol with an olefine fraction containing Ca-Crz olefines obtained in petroleum refining; also the polyglycol ethers obtained by condensing ethylene oxide with higher fatty alcohols such as oleyl alcohol and lauryl alcohol; also the polyglycol ether esters obtained by condensing ethylene oxide with oleic acid and the polyglycol ether obtained by condensing ethylene oxide with alkyl mercaptans such as tetrapropylene mercaptan.

These products may be characterized as liquid, non-ionic, polyglycol ether surface active agents and all of those tested were readily miscible with the hollow beaded alkali metal tetraborates in proportions up to about 40% by weight to give dry free-flowing materials from which the liquid did not separate. These liquid non-ionic polyglycol ether surface active agents are well known in the art, having been described, for example, in U. S. Patents Nos, 1,970,578, 2,213,477 and 2,205,021, and are readily obtainable as described in these patents by condensing an alkylene oxide, usually ethylene oxide, although other lower alkylene oxides such as propylene and butylene oxide may be employed if desired, with a water-insoluble monomeric organic compound, usually of a fatty or oily nature, and having an active hydrogen atom in the molecule such as organic carboxylic acids, hydroxy compounds (i. e. alcohols and phenols), amines, amides, mercaptans, etc. These products are a recognized class of non-ionic surface active agents and it is believed that all water-soluble surface active agents of this class which are normally liquid may be employed in preparing the novel detergent compositions of the present invention. In order to simplify the present specification, these products are referred to herein as liquid non-ionic polyglycol ether surface active agents. They may be represented by the following general formula:

wherein R is the residue, essentially hydrocarbon,

of a water-insoluble monomeric organic compound having a reactive hydrogen atom,

II II i. e. the residue of a group containing an active hydrogen, and n is an integer of at least 4 and generally 6 or higher, and R, and R" are hydrogen or lower alkyl.

While in the foregoing examples the borax (alkali metal tetraborate) was first pasted with a small amount of water and this paste heated with stirring, it should be understood that if desired, this pasting operation, although convenient on a small scale, may be omitted, since on heating the alkali metal tetraborates will first melt and then on continued heating with stirring will disintegrate into rather large granules which, on continued working and heating dry out and further disintegrate into small granules of the order of 0.1 mm. and on further heating the small granules then intumesce or puff up to form the novel hollow beaded products of the present invention.

All of the hollow beaded products obtained in the foregoing examples were readily watersoluble free-flowing products having a low bulk density. The hollow beads of the alkali metal tetraborates themselves had a bulk density of from 0.1 to 0.12 grams per cc. and were a particularly easily-handled and readily-soluble form of these materials and were suitable for all of the usual applications of alkali metal borates, particularly in washing and cleaning operations. The mixtures of the hollow beaded alkali metal tetraborates with the liquid non-ionic polyglycol ether surface active agents had a bulk density less than 0.3 gram per cc., usually 0.12 to 0.15 gram per 00., and were excellent detergents suitable for general application as household detergents. Wash waters containing these material are considered as having excellent detergency for china, glassware, woodwork and textiles, and are suitable for use as general-purpose household detergents, both in soft and hard water. In order to obtain a mixture which has the widest application as a detergent, at least 20% and preferably at least 25% by weight of the liquid non-ionic polyglycol ether surface active agent should be mixed with the hollow beaded alkali metal tetraborates. The amount of liquid non-ionic polyglycol ether surface active agents which may be incorporated in the hollow beaded alkali metal tetraborates may be increased up to about 40%, as previously indicated, while still retaining the dry free-flowing properties of the mixture and without any liquid separation. However, since the non-ionic polyglycol ether surface active agents are relatively more expensive than the alkali metal tetraborates from an economic standpoint, the use of more than about 35% thereof in the hollow beaded alkali metal tetraborates is not attractive, except for special purposes.

I claim:

1. A dry appearing free-flowing detergent composition consisting of hollow beaded alkali metal tetraborates having a particle size of about 1 mm. and a bulk density of about 0.1 gram per cubic centimeter containing from 20-40% by weight of a liquid non-ionic polyglycol ether surface active agent.

2. The method of producing a detergent composition comprising hollow beaded alkali metal tetraborates having a particle size of about 1 mm. and containing from 20 to 40% of a liquid nonionic polyglycol ether surface-active agent which comprises pasting an alkali metal tetraborate with a small amount of water and from 20 to 40% by weight of the tetraborate of a liquid non-ionic polyglycol ether surface-active agent, heating the beadshaving particle-size of about 10.1 mmaand heating the thus formed small ,dense beads :to

cause the same to intumesce and form saidhollow beads.

HERBERT L. SANDERS.

-BEFERENCES CITED The iollowin'g references Q2116 of record in the Number Number Number 10 330,453 469,334

:Name Date Black July 3,1934 Smith Dec. 17., .1935 Cram'er'et'aL. Oct. 4,1938 Sommer ,et 'a1., Mar. 21 1939 Nuesslein eta1., Nov. 23, 1943 FOREIGN PATENTS Country Date Great Britain June 12, 1930 GrsatBritain .J.u'1y 23,.1'93'7 

2. THE METHOD OF PRODUCING A DETERGENT COMPOSITION COMPRISING HOLLOW BEADED ALKALI METAL TETRABORATES HAVING A PARTICLE SIZE OF ABOUT 1 MM. AND CONTAINING FROM 20 TO 40% OF A LIQUID NONIONIC POLYGLYCOL ETHER SURFACE-ACTIVE AGENT WHICH COMPRISES PASTING AN ALKALI METAL TETRABORATE WITH A SMALL AMOUNT OF WATER AND FROM 20 TO 40% BY WEIGHT OF THE TETRABORATE OF A LIQUID NON-IONIC POLYGLYCOL ETHER SURFACE-ACTIVE AGENT, HEATING THE SAME WITH CONSTANT STIRRING TO FORM SMALL DENSE BEADS HAVING PARTICLE SIZE OF ABOUT 0.1 MM. AND HEATING THE THUS FORMED SMALL DENSE BEADS TO CAUSE THE SAME TO INTUMESCE AND FORM SAID HOLLOW BEADS. 